Stock futures spun lower ahead of Monday's open, as currency markets were in motion, but economic and earnings calendars were thin, with the main event being a speech from Federal Reserve chairman Ben Bernanke at the University of Michigan at 4 p.m. central time. Dow futures dipped 21 points were falling. Nasdaq 100 futures were also sliding, down 15.75 points. S&P 500 futures were off 2.25 points. Apple (AAPL) swooned 4% in premarket action,